This is a review and detailed measurements of the Magnepan LRS (Little Ribbon Speaker). It was kindly sent to me by a member and costs US $650.
Conclusions
The Magnepan LRS is a hugely flawed speaker with moments of delight. If I could control what you listen to, e.g. in an audio show or dealer room, I could convince you it is much better speaker than it is. The best way I can explain this is that the designers solved 30% of the physics of building a speaker, and threw you in there to solve the rest! You take on the job of spending what must be a lifetime messing with location, tilt, EQ, etc. to get sound that is good for more than a few select tracks.
I am confident a better job can be done than what we see in LRS. Maybe making the panels smaller causes the beaming and interference patterns worse. I don't know. What I do know that this is not a product finished and fit for use by a consumer.
I wonder how much simulation and in field analysis was performed as I have shown here. Doesn't seem like much was done to find and remove issues with this speaker.
Needless to say,
I can't recommend the Magnepan LRS.
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As always, questions, comments, recommendations, etc. are welcome.
Have to go and see if I can fix our dishwasher now.
Too cheap to pay someone $500 or more to fix this German invention. If you want me to consider hiring someone to fix it, please
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Thanks for an interesting review! A few points that struck me:
1. I'm not sure about HF response. Stereophile measured up to 19 kHz, after which it plummets like a rock.
2. HF drivers in dipoles are placed asymmetrically when possible because doing so produces the flattest response by averaging out dipole cancellation. I don't think the notch at 1 kHz is due to the asymmetry. Rather, I'm guessing that it's a characteristic of a first order Butterworth filter. Any causal filter it can be optimized for flat power response or flat on-axis response but not both. The difference here with the typical speaker is that the irregularity occurs horizontally rather than vertically.
3. Re vertical directivity, this is presumably why the speaker is tilted at an angle, to put you in the center of the tweeter when seated. This may be an issue for casual listening, less so for formal listening. At least one reviewer has criticized the HF response from a subjective perspective. In any case, dipoles aren't "anywhere in the room" speakers. Their horizontal polar pattern isn't optimized for that.
4. The LF response should be better than you measured when the LRS is in a room of moderate size. This could be a room mode/placement issue; dipole bass is notorious for disappearing in some rooms, being fine in others.
According to Magnepan, if the room is large, the LRS's lows will disappear, since the panel is so small -- the baffle of a dipole woofer has to be sized for the room, the larger the room, the larger the baffle. They don't recommend the LRS to someone who has a larger room -- as Wendell Diller put it, in larger room, the LRS turns into a midrange! My sense of hearing it at AXPONA in a hotel room was that it lacked deep bass, but was fine in the midbass. (I use to have a pair of MMG's, which are of similar size, and that was my reaction to them as well. They were good down to maybe 55 Hz and most guys put subs on them.)
5. Re near/far field -- complex with a line source, since the driver dimensions are different vertically and laterally, but in my experience, small dipoles like the LRS sound good in the near field, where they more closely approximate a line source in the highs and there is less baffle cancellation in the lows.
Many or most of the limitations you mention are a necessary consequence of the $650 cost of the speaker. These tradeoffs are different for a dipole speaker than they would be for a conventional one. In a dipole, a larger baffle would mean deeper bass, a narrow true ribbon tweeter would have superior horizontal dispersion, a full-height line source would have smoother vertical response, etc. With a box, you'd hear different trades.
In my experience, small dipoles like the LRS come into their own with acoustical music. That's where you'll hear the spatial magic. You don't say how far you had them from the front all -- dipoles need to be at least 3 feet, preferable 5 feet or more from the front wall to do their magic. Also where the compromise is best, since the rear reflections of a dipole will tend to increase the sense of depth while side reflections will tend to increase the sensation of width, meaning I think that dipoles are better when you want the musicians beyond the wall while cardioids are better when you want the musicians right in front of you. (Of course, ideally, it's the recording that determines this, but for that to happen, early reflections in the room have to be at least 20 dB down to more than 20 ms out so as not to anticipate the early reflections on the recording, and most home listening rooms don't do that, though a dipole out from the front wall can come close, hence their reputation for depth.)
Acoustical music is also where you'll hear detail (likely a consequence of the waterfall) and the lack of the "boxiness" that's heard in inexpensive box speakers. For rock, or for a larger room, people are going to want a sub, and the LRS may not be the best choice. The people who like it for rock are apparently those who want to hear all the details in the recording, and they almost always use it with a sub.
Any dipole requires experimentation and paintstaking placement, but the positive side of that is that they don't require much acoustical treatment for optimal response. This also means that a room that is tuned for box speakers will sound too dead with a dipole -- dipoles do best with the Rt of a typical living room.
I think the fact that the LRS sounds good with typical show demo tracks says a lot. This is a speaker that produces unusually natural results with acoustical recordings and I haven't heard a $650 box that comes close to it in that regard. For rock or a larger room, I think I'd want a sub, or a larger dipole or a conventional speaker. Based on what I heard, the LRS is a killer budget speaker for those who listen to acoustical music and are willing to spend time on speaker placement (and with dipoles, do I mean time!) At AXPONA, it was jaw-droppingly good for the price on recordings of acoustical music.
